JP2000101306A - Dielectric filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure proper connection between conductor path terminals on a printed circuit board and input output pads. SOLUTION: In this dielectric filter, each solder resist layer 10 is formed around input output pads 6, 6 formed on the dielectric filter 1, while being insulated from an outer conductor 7 by a conductor removed part 9 in a way of being protruded onto the circumferential part of the input output pads 6, 6 from on the conductor removed part 9 or onto the outer conductor 7 from on the conductor removed part 9. Thus, the connection area of the input output pads 6, 6 to conductor path terminals which depend on exposed parts of them can be selected arbitrarily, and the connection is ensured. Furthermore, the width of the solder resist layer 10 is designed larger than the width of the conductor removed part 9, to prevent occurrence of a short-circuit caused by a mount error, even when a mount position of the dielectric filter 1 has an error because there is no bridge-over contact for the conductor path terminals 21, 21 of a printed circuit board 20 onto the input output pads 6, 6 and the outer conductor 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a dielectric filter having a plurality of resonators arranged in parallel.

[0002]

2. Description of the Related Art A plurality of resonators are provided on a dielectric ceramic block by coating an inner conductor on an inner peripheral surface of a through hole, and a required outer peripheral surface excluding an open end surface where the through hole is opened. Various types of dielectric filters in which an outer conductor is coated are provided.

[0003]

In the structure of the above-described dielectric filter f, as shown in FIG. 8, the resonators b on both outer sides are located on the side surfaces of the dielectric ceramic block near the open end faces. A dielectric filter is disclosed in which input / output pads p, p, which are capacitively coupled to the resonators b, b, are formed so as to be insulated from the outer conductor d (see, for example, JP-A-3-124101). I have.

In such a configuration, the input / output pads p, p
Is provided so as to face the resonators b, b, so that the conductive layer is removed in a rectangular shape around the input / output pads p, p to form a conductor removed portion c, whereby the input / output pads p, p Are insulated from the outer conductor d. At this time, each of the resonators a, b, and b is designed to have a length substantially equal to λ / 4 of the resonance frequency. However, if the width of the rectangular conductor removing portion c is wide, the resonators b, b, and b , The resonance frequency of the resonators b and b becomes high due to the influence, and the resonance frequency becomes inconsistent with that of the central resonator a, whereby good filtering characteristics cannot be obtained. For this reason, the removal width of the rectangular conductor removal portion c is formed as narrow as possible.

In order to obtain a predetermined filtering characteristic, a predetermined capacitive coupling is necessary, which is adjusted by the area of the input / output pads p, p. Therefore, the shape of the input / output pads p, p is specified. Is done.

For these reasons, the shape of the input / output pads p, p is set to have a predetermined area, and the width of the conductor removing portion c is set to be small.

Incidentally, the input / output pads p, p are connected to the conductive path end on the printed circuit board in a mounted state, but the size of the input / output pad and the conductive path end may not match. In this case, if the input / output pads p, p are larger than the conductive path end, the input / output pads p, p may straddle the conductive path end and the conductor around it, causing a short circuit on the printed circuit board. .

If the input / output pads p, p are smaller than the end of the conductive path, the width of the conductor removing portion c is set as narrow as possible, as described above. Over the input / output pads p, p, a short circuit may occur on the dielectric filter f side.

Furthermore, even if there is an error in the mounting position of the dielectric filter, the conductive path end straddles the input / output pad and the outer conductor, or the input / output pads p and p form the conductive path end and the surrounding area. In some cases, a short circuit may occur due to contact with a conductor. SUMMARY OF THE INVENTION It is an object of the present invention to secure a proper connection between a conductive path end on a printed circuit board and an input / output pad.

[0010]

A first means of the present invention is to provide a dielectric ceramic block in which a plurality of resonators formed by coating an inner conductor on an inner peripheral surface of a through hole are arranged side by side; An outer conductor is coated on a required outer peripheral surface excluding an open end surface where a through hole is opened, and an input / output pad that is capacitively coupled in opposition to the resonator at a position near the open end surface of the resonator on a side surface of the dielectric ceramic block. A dielectric filter defined by an outer conductor and a conductor-removed portion, wherein the solder filter layer protrudes inward from the conductor-removed portion onto the peripheral edge of the input / output pad to form a solder resist layer. is there.

In this configuration, when the input / output pad is larger than the conductive path end, the solder resist layer is formed so as to protrude inward on the peripheral edge of the input / output pad, and the exposed area thereof is made equal to the conductive path end. are doing.

A second means of the present invention is a dielectric filter characterized in that a solder resist layer is formed so as to protrude outward from the conductor removing portion onto the outer conductor and form a solder resist layer.

In such a configuration, when the input / output pad is smaller than the conductive path end, the solder resist layer is formed so as to protrude outward on the outer conductor so that the conductive path end is not connected to the outer conductor.

In both of these configurations, the input / output pad is insulated from the outer conductor by the narrow conductor removing portion. On the other hand, the conductor around the conductive path end of the printed circuit board on which the dielectric filter is mounted and the input / output pad are insulated by the solder resist layer. Therefore, even if the shape of the input / output pad does not match the shape of the end of the conductive path, it can be adjusted by the solder resist layer, and the electrical connection can be easily secured.

In addition, even if the solder resist layer is formed so as to protrude largely inside and outside the conductor-removed portion, it does not affect the substantial length of the resonator. Therefore, even if there is an error in the mounting position of the dielectric filter, a short circuit can be easily prevented.

[0016]

1 and 2 show three resonators 3a and 3a.
An embodiment in which a three-stage dielectric filter 1 in which resonators are respectively constituted by b and 3b is shown. Here, the dielectric porcelain block 2 has a substantially rectangular parallelepiped shape made of a ceramic dielectric such as a BaO-TiO ₂ system, a BaO-TiO ₂ -rare earth oxide system, and the resonators 3a, 3b, 3b are mutually connected. They are arranged in parallel and in the plane direction. These resonators 3a, 3
b, 3b are respectively connected to the inner conductors 5, 5 in the through holes 4a, 4b, 4b.
5 and 5 are formed by coating.
The outer conductor 7 is coated on a required outer peripheral surface excluding the open end surface 8 where the openings a, 4b and 4b are opened, and this is used as a shield electrode. The resonators 3a, 3b, 3b are made to substantially match the resonance length dimension corresponding to about λ / 4 of the resonance frequency.

Next, the main part of the present invention will be described. At the position near the open end face 8 on the side of the dielectric ceramic block 2, the input / output pads 6, 6 that are capacitively coupled to the outer resonators 3 b, 3 b are connected to the outer conductor 7 by the rectangular conductor removing portion 9. It is formed by partitioning it into an insulating shape. These input / output pads 6,6
Are electrically connected to the ends of the conductive path on the printed circuit board. These input / output pads 6, 6 are adjusted to have a required area in order to obtain a predetermined input / output capacity. Further, the conductor removing portion 9 is set as narrow as possible, so that the substantial length of the resonators 3b, 3b on both sides is not shortened with respect to the central resonator 3a, and the mismatch of the resonance frequency is eliminated. I try to deter them.

3 and 4 according to the first means of the present invention.
As shown in the figure, the solder-resist layer 10 made of an insulating material protrudes inward from the conductor removing portion 9 onto the peripheral edges of the input / output pads 6 and 6, and is formed into a rectangular pattern by screen printing. That is, input / output pads 6, 6
Is larger than the conductive path end 21 of the printed circuit board 20 on which the dielectric filter 1 is mounted.
The portion where the input / output pads 6 and 6 are larger than 1 is covered with the solder resist layer 10, and insulation between the input and output pads 6 and 6 and the conductor 22 around the conductive path end 21 is ensured.

As a result, the exposed area of the input / output pads p, p becomes the connection area with the conductive path end 21, so that short-circuiting on the printed board over the conductor 22 around the same may occur. Absent.

FIGS. 5, 6, and 7 show the second means of the present invention. In this structure, the solder is formed by projecting outward from the conductor removing portion 9 onto the outer conductor 7 and forming an insulating paint. The resist layer 10 is formed into a rectangular pattern by screen printing or the like. That is, the input / output pads 6,
6 is a printed circuit board 20 on which the dielectric filter 1 is mounted.
Is smaller than the conductive path end 21, the solder resist layer 10 is formed so as to protrude outward on the outer conductor 7, whereby the conductive path end 21 is insulated from the outer conductor 7.

In both configurations, the solder resist layer 10
Does not change the resonance length even if it is formed so as to protrude into and out of the conductor removing portion 9 without any problem.
It can be wide. For this reason, even if there is an error in the mounting position of the dielectric filter 1 on the printed circuit board 20, the conductive path end 21 does not contact the input / output pads 6 and 6 over the outer conductor 7, and the mounting error occurs. Short circuit can be prevented.

Here, an epoxy resin or the like is used for the solder resist layer 10. The layer thickness is 50 to 300
μm and is applied by screen printing.

[0023]

As described above, according to the present invention, the dielectric filter is provided on the periphery of the input / output pad formed insulated from the outer conductor by the conductor-removed portion. Or, since the solder resist layer is formed by protruding from the conductor removal portion onto the outer conductor, the connection area with the conductive path end determined by the exposed portion of the input / output pad can be arbitrarily selected. The connection can be ensured, and the solder resist layer is wider than the conductor removal part, so that even if there is an error in the mounting position of the dielectric filter, the conductive path end will be This makes it possible to prevent a short circuit due to a mounting error, which is an excellent effect.

[Brief description of the drawings]

FIG. 1 is a perspective view of a dielectric filter 1 according to an embodiment of the present invention as viewed from below.

FIG. 2 is a cross-sectional side view of the dielectric filter 1.

FIG. 3 is a bottom view of the dielectric filter 1. FIG.

FIG. 4 is an enlarged vertical sectional side view of a main part showing a manner in which a solder resist layer 10 is applied.

FIG. 5 is a perspective view seen from below of a dielectric filter 1 according to another configuration of the present invention.

FIG. 6 is a bottom view of a dielectric filter 1 having another configuration of the present invention.

FIG. 7 is an enlarged vertical sectional side view of a main part showing a manner of applying a solder resist layer 10 in another configuration of the present invention.

FIG. 8 is a perspective view of a conventional dielectric filter f.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Dielectric filter 2 Dielectric porcelain block 3a, 3b, 3b resonator 5 Inner conductor 6 I / O pad 7 Outer conductor 9 Conductor removal part 10 Solder resist layer 20 Printed circuit board

Claims (2)

[Claims] 1. A plurality of resonators formed by coating an inner conductor on an inner peripheral surface of a through hole in a dielectric ceramic block, and a required outer peripheral surface excluding an open end surface where the through hole is opened. And an input / output pad that is capacitively coupled in opposition to the resonator at a position near the open end face of the resonator on the side surface of the dielectric porcelain block. What is claimed is: 1. A dielectric filter, comprising: a solder resist layer formed so as to protrude inward on a peripheral edge of an input / output pad from above a conductor removal portion. 2. A plurality of resonators formed by coating an inner conductor on an inner peripheral surface of a through hole in a dielectric ceramic block, and a required outer peripheral surface excluding an open end surface where the through hole is opened. And an input / output pad that is capacitively coupled in opposition to the resonator at a position near the open end face of the resonator on the side surface of the dielectric porcelain block. What is claimed is: 1. A dielectric filter, comprising: a solder resist layer formed so as to protrude from a conductor removal portion onto an outer conductor to form a solder resist layer.